My wife and I are building new systems, and we need to know if the Z170 FTW is compatible with the Samsung 950 pro 512GB M.2 M key SSD. I have read a review on newegg and one thread on this forum that both indicate that there may be a problem with the SSD on this board. I would love it if this were not the case, since I would rather use an EVGA board than one from another manufacturer.
 
Thank you for your time.

Yes it works.....but using the m.2 disables the marvel and intel SATA ports. I didn't know this ahead of time.

FWIW, I just spent the holiday getting my and my wife's systems to boot from Samsung 950 PRO.  Starting out we were each running Win10 free upgrades of Win7 systems.  My wife had recently decided to do a clean install of Win10 which we ignorantly did onto an MBR formatted drive and she adamantly refused to redo her system again, so to get it done I had to both switch to UEFI from legacy and convert to GPT from MBR.  I did a clean install on my system (twice thanks to clumsy Microsoft support while reauthorizing my Win10 license) and I was using my system for work at the same time so I moved my old boot drive to an external sata port and got used to rebooting with M.2 off to do work and then with M.2 on to work on my system conversion.  The most important takeaways were to disable CSM always before booting with M.2 enabled and to use free Macrium Reflect restore image to do the MBR to GPT conversion.  Also upgrade all firmware as necessary to support UEFI; my FirePro W7000 was not UEFI enabled but AMD went above and beyond to help me get it there.  I really like the FTW now that I have wrestled with it for awhile.  Just be ready to learn.